Circuit breaker



Nov. 2, 1954 J. A. DROBNEY EI'AL Y 2,693,516

CIRCUIT BREAKER Filed Oct. 18, 1951 Fig.l.

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United States Patent CIRCUIT BREAKER Joseph A. Drobney and Melvin Bingenheimer Beaver, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa.,- a corporation of Pennsylvania Application October 18, 1951, Serial No. 251,942

9 Claims. (Cl. 200-.116)

predetermined abnormal conditions.

An object of this invention is to provide an improved circuit breaker having an insulating housing in which the moving parts of the circuit breaker are supported without the use of a metal frame.

Another object of this invention is to provide an improved circuit breaker having a molded insulating housing in which the supports for the moving parts of the circuit-breaker are molded integral with the housing.

Another object of the invention is the provision of a circuit breaker as previously described which is simple and inexpensive to manufacture and which has a minimum number of parts.

The novel. features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, both as to construction and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in conjunction with the accompanying drawing.

In said drawing:

Figure 1 is a side elevational view, with the cover plate removed and the housing shown partly broken away, of a circuitbreaker embodying the principles of the invention.

Fig. 2 is a sectional view taken on line Il-II of Fig. 1 and looking in the direction of the arrows.

Referring to the drawing, the circuit breaker comprises a housing 11 and a cover plate 13 (Fig. 2) both of molded insulating material, stationary contact means 15 and cooperating movable contact means 17, operating mechanism indicated generally at 19 and a trip device 21. The stationary contact 15 is rigidly mounted on the inner end of a terminal conductor 23 which extends outwardly through an opening in the adjacent end wall of the housing 11 and has a connecting means, such as a terminal screw 25, on its outer end. The movable contact 17 is rigidly mounted on one end of a switch member or arm 27 pivotally supported at its other end on a pivot member 29 of insulating material which is molded integral with the side wall of the housing 11.

The switch arm 27 is biased closed by a compression spring 31 having one end seated in a spring seat 32 in the base of the housing 11 and the other end engaging a spring seat on the under side of the switch arm 27. An operating lever 33, preferably of a molded insulating material, is pivotally mounted on a pivot 35 molded integral with the side wall of the housing 11, and has a cam surface 37 on the inner end thereof adapted, upon clockwise movement of the lever 33, to engage a pin 39 in the switch arm 27 and move the switch. arm counter-clockwise to an open position in which a recess 41 in the lever 33 engages the pinr39 to hold the-switch arm 27 in the open position.

The operating lever-33 is provided wtih an integral handle'member 43 extending outwardly through an opening 45in the housing and an integral arcuate portion 47 of thehandle substantially closes the opening 45 in all positions of the handle.

The contacts are manually opened by clockwise movement of the handle 43 and the operating lever 33 to the off position. During this movement, the cam surface 37 acts on the pin 39 to move the switch member 27 to 8 the open position further compressing the spring 31.

2,693,515 Patented Nov. 2, 1954 2 Movement of the handle 43 and the operating lever 33 counter-clockwise'from the off to the on position permitsthe spring 31- to move the switch member 27 to the closed position to, close. the contacts.

Pivotally mounted on the pivot member 35 isa releasable member 49 which may be of. an insulating material, and is biased in,a counter-clockwise direction by means of a spring-:51 having one end seated in a spring seat 52 in-the adjacent'endwall of the housing and the other end engaging a s ring guide 53 on the releasable member 49.: The spring 53 biases the releasable member 49 with a small momentarm thereby providing a light latch load.

Referringto Fig. Zofthe drawing, the operating lever 33 and the releasable member 49 are pivotally supported onthe pivot member :35 and the portions thereof which cooperate with the pin 39 on the switch. arm 27 are disposed on opposite sides of the switch arm. Shoulders on the pivotmembers '35 and29, respectively, servevto locate the releasable member 49 and the switch arm 27 relative to the side Wall of the housing 11, and the cover plate 13 :holds the'parts in proper positon. The cover plate 13 .iseidzill position by a screw 48 (Figs. 1 and 2) extending through an opening in the pivot member 35 and screws (Fig. .1) extending through the lower corners ,.,of the housing and the cover plate.- It will be understood that othersultable means, such as rivets, or eyelets, may be ,used to secure the cover-plate 13 tothe housing 11.

The releasable member 49 is normally biased by the spring 51 in a counter-clockwise direction, but it is normally releasablyrestrained in operative position by the trip. device, 21.- Operation of the trip device releases the releasable member 49 whereupon thespring 51, which isqof considerably greater strength than the contact spring 31, rotates. thexreleasable member=49 sharply counterclockwise.- During counter-clockwise movement 'of releasablemember 49, the moment arm-of spring 51 increases; and this. movement causes a cam surface 55 on the releasable-member 49 to engage the pin 39 and move thepswitchmember, 27 to the open position.

When the switch member27 ,is automatically moved to the open=positiontby the releasable member 49,. the handle 43 is moved-toan intermediate indicating position by means of a spring .57 havingone end seated in a spring seat in the housing 11 and bearing against one end of the arcuate portion 47 of the handle.

The releasable member 49 is reset and relatched and the contacts closed'following an automatic opening operation by first moving the handle clockwise to they full off: position and then counter-clockwise. to the on position.- When thehandle 43 is moved to the off position, a surface 59 on the arcuate portion 47 thereof engages and moves the releasable member 49 to its normally restrained position. Counter-clockwise movement of the handle 43 then, permits the spring 31 -to close the contacts.

The trip devicev 21 comprises a bimetal element 61 having its lower end rigidly secured to the inner end of a terminal conductor.63 supported by means of a screw 65 on the end wall of the housing '11, and having a portion'extending out through an opening in the end wall of the housing. A terminal conductor 67 is secured to the outer endof the conductor 63. The upper or free end of the bimetal element 61 is connected by means of a flexible conductor 69 to thepivoted end of the switch arm 27. A latch member 71' secured to the bimetalelement engages a latching portion 73 of the releasable member 49 and releasably restrains the releasable membet in operative position. When an overload current occurs, the bimetal element '61 becomes heated and bends toward the right causing the latch 71 .to release the releasable member whereuponthis member functions in the previously described manner to effect opening movement of the switch member.

Means is provided for calibrating the trip device. This means comprises a screw 75 threaded into the terminal conductor 63 at-the point Where the bimetal element 61 is mounted thereon. The screw 75 has a rounded head 77 "seated in a recess in the end wall of the housing 11. An opening 79 is provided in the end wall for the inser- 0 tion of a screw driver to turn the screw 75. Turning the screw 75 will cause bending of the conductor 63 and corresponding variation of the position of the bimetal element 61 according to the direction in which the screw 75 is turned to thereby vary the tripping point of the circuit breaker.

It will be seen that the invention provides a circuit breaker in which the molded housing forms the sole supporting frame and supports all of the parts of the circuit breaker without the use of a separate metal frame, the parts being supported in their proper positions in the housing by recesses and surfaces molded in the housing. The pivots for the moving parts of the circuit breaker are molded integral with the housing. None of the parts of the breaker are supported or partially supported by the cover plate which facilitates assembly of the circuit breaker and permits removal of the cover plate for purposes of inspection and replacement of parts without disturbing the calibration of the circuit breaker.

Having described the invention in accordance with the provisions of the patent statutes, it is to be understood that various changes and modifications may be made in the structural details and combinations of elements disclosed without departing from some of the essential features of the invention.

We claim as our invention:

1. A circuit breaker comprising a housing of one-piece molded insulating material, stationary and movable contact means, a pivoted switch member biased closed and movable to open and close said contact means, manually operable means for engaging and moving said pivoted switch member to open position against its normal bias, a releasable member operable when released to engage and automatically move said pivoted switch member to open position against its normal bias, and a single pivot pivotally supporting said manually operable means and said releasable member comprising a pivot member supported on said molded housing.

2. A circuit breaker comprising a housing of molded insulating material, relatively movable contact means, a pivoted switch member biased closed and movable to open and close said contact means, a pivoted operating lever movable to engage and move said switch member to open position against its normal bias, a pivoted releasable means operable when released to engage and move said pivoted switch member to the open position against its normal bias, pivot means for pivotally supporting said pivoted parts comprising a pivot member molded integral with said housing supporting both said operating lever and said releasable means, and a separate pivot member supported on said housing supporting said switch member.

3. A circuit breaker comprising a housing of molded insulating material, stationary and movable contact means, a pivoted switch member biased closed and movable to open and close said contact means, a projection on said switch member extending on both sides of said switch member, a manually operable lever having cam means thereon disposed on one side of said switch member fo engaging said projection and moving said switch membeto open position, a releasable member having cam means thereon disposed on the other side of said switch member operable when released to engage said pI'O]6CtlO]1 and automatically move said switch member to open positior and common pivot means for said manually operable leve and said releasable member comprising a pivot member molded integral with said housing.

4. A circuit breaker comprising stationary and movable contact means, a pivoted switch member biased closed and movable to open and close said contact means, a pin mounted in said switch member and extending transversely on both sides thereof, manually operable means having a portion disposed on one side of said switch member for engaging said pin and moving said switch member to open position, a releasable lever having a portion disposed on the other side of said switch member operable when released to engage said pin and automatically move said switch member to open position.

5. A circuit breaker comprising relatively movable contact means, a pivote switch member movable to open and closed positions to open and close said contact means, biasing means biasing said switch member to closed position, a pin on said switch member extending on both sides thereof, manually operable means having a cam portion disposed on one side of said switch member movable to one position to engage said pin and move said switch member to open position, said manually operable means being movable to another position to permit said biasing means to move said switch member to closed position, and releasable means having a cam portion disposed on the other side of said switch member operable when released to engage said pin and move said switch member to open position irrespective of the position of said manually operable means.

6. A circuit breaker having stationary and movable contact means, a pivoted switch member having a projection on each side thereof, said switch member being biased closed and movable to open and close said contact means, manually operable means movable to open and closed positions and having cam means disposed on one side of said switch member cooperating with said projection to eiiect opening and closing movements of said switch member, a releasable member having cam means thereon disposed on the other side of said switch member cooperating with said projection to effect automatic opening movement of said switch member upon release of said releasable member, and spring means operable upon automatic opening movement of said switch member to move said manually operable means to an indicating position.

7. A circuit breaker having a pivoted switch arm movable to open and close the circuit, manually operable means movable to an open and to a closed position and having a cam surface thereon disposed on one side of said switch member, said cam surface being engageable with said switch member to move said switch member to open position, a releasable member having a cam surface thereon disposed on the other side of said switch member, a first spring biasing said releasable member to engage said switch member and automatically move said switch member to open position, and a second spring normally biasing said manually operable means toward open position and operable when said switch member is automatically moved to open position by said releasable member to move said manually operable means to an intermediate indicating position.

8. A circuit breaker comprising relatively movable contact means, a pivoted switch arm movable to open and close said contact means, manually operable means for engaging and moving said switch arm to open said contact means, a pivoted releasable member operable when released to engage and automatically move said switch arm to open said contact means, a trip device normally releasably restraining said releasable member in operative position, biasing means engaging said releasable member in a direction to engage and automatically move said switch arm to open said contact means, said biasing means engaging said releasable member at a point to provide a moment arm which is small at the latched position to provide a light latch load, but which is increased by pivotal movement of said releasable member when released.

9. A circuit breaker comprising relatively movable contact means, a pivoted switch member movable to open and close said contact means, a manually operable lever having cam means thereon for engaging and moving said switch member to open position, a releasable member having cam means thereon for engaging and moving said switch member to open position, spring means biasing said releasable member in a direction to engage and move said i switch member, a trip device normally releasably restraining said releasable member in operative position and operable in response to overload currents to release said releasable member, a single pivot pivotally supporting said manually operable lever and said releasable means, and the line of action of said spring means extending adjacent said pivot in the closed position of said breaker to provide a light latch load.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,308,401 Taylor Jan. 12, 1943 2,320,437 Jennings June 1, 1943 2,362,051 Cole Nov. 7, 1944 2,381,294 Langstroth Aug. 7, 1945 

